One swimming in wine staggered (6)
I believe the answer is:
reeled
'staggered' is the definition.
('reel' can be a synonym of 'stagger')
'one swimming in wine' is the wordplay.
'one swimming' becomes 'eel' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'wine' becomes 'red' (red is a type of wine).
'eel' inserted inside 'red' is 'REELED'.
Can you help me to learn more?
(Other definitions for reeled that I've seen before include "Staggered around as if drunk" , "Staggered - having done Irish dance?" , "Wound up" , "Staggered in a dance perhaps" , "Felt giddy or bewildered" .)